This invention pertains to the field of immunology. More specifically, this invention provides a novel method of isolating pre-selected antigen-specific T-lymphocytes from a biological sample.
The isolation of T cells has been generally accomplished using lengthy procedures that involve a series of antigen stimulations in the presence of autologous antigen-presenting cells (APCs) which result in an increase in the clonal frequency of the T cells specific for the particular peptide bearing APC. The increased clonal frequency is a result of APC-induced proliferation of the T cell specific for the particular APC. Limiting dilution is often used to select for the growth of the targeted cell (see, for example, pp 3.15.9-12 in Current Protocols in Immunology, Coligan et al. (eds) (1991). The reliance on cell division to obtain a clonal population of cells makes this method a long and slow process requiring extensive labor and attention.
In addition, the binding of a specific antigenic peptide can occur with different affinities to any of the various and different MHC class II molecules expressed on APCs (Valli et al. J. Clin. Invest., 91:616-628 (1993). Thus there is no guarantee using prior art methods that T cells specific to a particular MHC restriction type will be isolated. The MHC restriction type of the T cells that are isolated must be determined empirically after isolation and specific MHC restriction types cannot be dictated prior to isolation.